The present invention relates to a fuel injector for supplying fuel to an engine.
Japanese Laid-Open Patent Publication No. 2-163460 discloses a known art in which-a fuel metering portion for metering the rate of injection is disposed in the fuel passage between a valve case upstream of an injection nozzle port and a valve member.
An example of the fuel metering portion is shown in FIG. 7. The fuel metering section 100 is adapted to meter the fuel by cooperation between the inner peripheral surface of the valve case 101 and an annular flange 103 provided on a valve member 102 so as to adjust the rate of injection of fuel. A plurality of metering surfaces 104 along which the fuel flows are provided in the outer peripheral surface of the flange 103.
In the conventional method of producing a fuel injector, the fuel metering portion 100 is formed by cutting the flange peripheral surface to form the metering surfaces 104 so as to increase the area of the flow passage. These metering surfaces 104 are formed to extend in parallel with the axis of the valve member 102.
To obtain the desired fuel injection rate, measurement of the fuel injection rate and cutting of the metering surfaces 104 are repeatedly conducted until the desired rate is attained.